package com.cjl.multi_thread.aqs;

import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.AbstractQueuedSynchronizer;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;

public class Mylock implements Lock {

    private final static Sync sync = new Sync();

    @Override
    public void lock() {
        sync.tryAcquire(1);
    }

    @Override
    public void lockInterruptibly() throws InterruptedException {
        sync.tryAcquire(1);
    }

    @Override
    public boolean tryLock() {
        return sync.tryAcquire(1);
    }

    @Override
    public boolean tryLock(long time, TimeUnit unit) throws InterruptedException {
        return sync.tryAcquire(1);
    }

    @Override
    public void unlock() {
        sync.tryRelease(0);
    }

    @Override
    public Condition newCondition() {
        return sync.newCondition();
    }

    static class Sync extends AbstractQueuedSynchronizer {

        Condition newCondition(){
            return new ConditionObject();
        }

        @Override
        protected boolean isHeldExclusively() {
            return getState() == 1;
        }

        @Override
        protected boolean tryAcquire(int arg) {
            if (compareAndSetState(0,1)){
                setExclusiveOwnerThread(Thread.currentThread());
                return true;
            }
            return false;
        }

        @Override
        protected boolean tryRelease(int arg) {
            if (getState() == 1){
                setExclusiveOwnerThread(null);
                setState(0);
                return true;
            }
            return false;
        }
    }
}
